Layered double hydroxide (LDH)-derived zinc oxide (ZnO) nanorod on exfoliated graphene oxide (GO) nanosheet for photocatalytic dye degradation and hexavalent chromium reduction

Abstract

A new low-temperature facile chemical decomposition of layered double hydroxide (LDH) has been developed for the large-scale controlled synthesis of zinc oxide (ZnO) nanorod on exfoliated graphene oxide (GO) nanosheet. ZnAl-LDH/GO composite precursor was prepared via in situ growth of the LDH on the exfoliated GO nanosheets. Thermo-chemical decomposition of ZnAl-LDH/GO composite at 80 °C produced highly dispersed ZnO nanorods on GO nanosheets. Although, neat ZnAl-LDH produces ZnO nanoparticle aggregates in the absence of GO. The morphology and properties of ZnO nanorods/GO nanocomposite was studied by X-ray diffraction analysis (XRD), transmission electron microscopy (TEM), UV–vis spectroscopy, Fourier transform infrared spectroscopy (FTIR), and thermogravimetric analysis (TGA). The band gap engineering of the nanocomposite was evaluated by varying GO content. The ZnO/GO nanocomposites materials exhibited excellent photo-catalytic activity towards the degradation of methylene blue (MB) and Cr(VI) reduction under the irradiation of direct sunlight at ambient condition. GO plays a crucial role in the directional growth of nanorods and enhances the photocatalytic activity of ZnO nanorods via the synergistic hole formation and electron transfer effect for the potential remediation of waste water.